JP3799599B2 - Welding apparatus and welding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a welding apparatus and a welding method for melting and welding cylindrical members in a circumferential direction with another cylindrical member inserted inside the cylindrical member by energy applied from two or more applying means.
[0002]
[Prior art]
Conventionally, when two or more types of cylindrical members are melted and welded over the entire circumference, it is common to apply the energy generated by the energy source from one direction and perform the entire circumference welding. For example, as shown in FIG. 8, an inner cylinder member 201 having the same cross-sectional shape as the outer cylinder member 200 is press-fitted inside the cylindrical outer cylinder member 200, and the optical head 210 is disposed outside the outer cylinder member 200. It is conceivable to irradiate the outer cylinder member 200 with the laser 211 generated by the laser generator and weld the outer cylinder member 200 and the inner cylinder member 201 over the entire circumference while rotating both the cylinder members. However, when energy is applied to only one part of both tube members and welding is performed over the entire circumference, the relative thermal strain balance between the unmelted part, the part to which energy is applied and the part that has been melted, and the part that has started to solidify, Both cylindrical members are deformed from the shape 220 before welding of both cylindrical members shown in FIG. 9A in a direction orthogonal to the direction in which energy is applied as shown in FIG. 9B. The cross section of the welded portion of the wire is deformed into an ellipse.
[0003]
The process of ovalization of the welded portion that occurs when all-around welding is performed by adding the energy generated by the energy source from one direction will be briefly described.
The deformation of the cylindrical member before welding occurs, for example, when another cylindrical member is press-fitted and assembled inside the cylindrical member. And the deformation | transformation becomes large with the balance of the expansion | swelling and shrinkage | contraction of the member by welding, and it deform | transforms into an elliptical shape. Even if it is a shape close to a perfect circle without deformation as shown in FIG. 9A before welding, it is deformed as shown in FIG. 9B after welding. The shape 221 after welding tends to be deformed into an oval shape from the shape 220 before welding close to a perfect circle in a direction intersecting the energy application direction at the welding start position. The dashed-dotted circles shown in FIG. 9 indicate the inner diameter and outer diameter of the welded part.
[0004]
Regardless of the presence or absence of deformation before welding, when the welding angle is in the range of 90 °, the cylindrical member becomes elliptic due to thermal expansion, and the amount of deformation increases. In the range where the welding progresses and the welding angle is 180 °, the ovalization is alleviated and the deformation is reduced by the expansion accompanying the progress of the welding and the shrinkage caused by the start of solidification in the first half of the welding. When welding progresses and the welding angle is in the range of 270 °, the expansion accompanying the progress of welding overlaps with the shrinkage caused by solidification in the first half of the welding, so that the deformation due to ovalization increases again. When the welding progresses and the welding angle is in the range of 360 °, the ovalization is mitigated by the expansion accompanying the progress of the welding and the shrinkage due to the solidification in the first half of the welding, and the deformation amount is reduced. Although the amount of deformation increases or decreases depending on the welding angle, the cylindrical member is deformed into an elliptical shape by welding. Even if the welding angle is set to 360 ° or more and the same portion is welded a plurality of times, the welded portion follows the same deformation process.
If the shape of a member that requires a metal seal is deformed by welding, there is a problem that the sealing performance is deteriorated.
[0005]
[Problems to be solved by the invention]
In order to suppress the deformation of both cylinder members by applying energy from one direction, it is conceivable to apply energy to two locations of both cylinder members from a direction facing 180 ° as shown in FIG. However, there are two places where energy is applied to the outer side of the outer cylinder member 200 and the inner cylinder member 201 on the opposite side in the radial direction and are easily deformed. That is, since there are two factors that cause ovalization in the same direction, both the cylindrical members are easily deformed in a direction orthogonal to the energy application direction. Therefore, the shape 231 after welding shown in FIG. 11B is elliptical in the direction intersecting the energy application direction at the welding start position from the shape 230 before welding shown in FIG. Deform. The circles shown by alternate long and short dashed lines in FIG. 11 indicate the inner diameter and outer diameter of the welded portion being deformed.
[0006]
Moreover, when the foreign material is mixed in the location where energy is applied and melted, the foreign material may evaporate due to the applied energy, and pores may be formed in the welded portion. If pores occur in the welded portion, there is a risk of poor welding.
[0007]
An object of the present invention is to provide a welding apparatus and a welding method for preventing deformation of a cylindrical member and correcting deformation of a welded portion before welding when the cylindrical members are melt-welded in the circumferential direction. .
Another object of the present invention is to provide a welding apparatus that reduces fuel leakage from an injector.
Another object of the present invention is to provide a welding method for preventing the generation of pores in a welded portion.
[0008]
[Means for Solving the Problems]
According to the welding device of the first aspect of the present invention, the application means for applying the energy generated by the energy source to the cylindrical member is arranged at two locations in the circumferential direction of the cylindrical member, and the application means are formed around the cylindrical member. When the angle is θ °, 80 ≦ θ ≦ 100. In other words, the applying means melts the portions that are approximately 90 ° apart at the circumferential angular positions of the cylindrical members and welds the cylindrical members together. Since the portion 90 degrees apart at the circumferential angular position of the cylindrical member melts, the cylindrical member tends to deform in directions orthogonal to each other. Since deformation of the entire welded portion of the cylindrical member is uniform, deformation of the welded portion of the cylindrical member can be prevented. Moreover, since the deformation of the entire welded portion of the cylindrical member becomes uniform, the shape of the welded portion that has been deformed before welding can be corrected. For example, when the operation of inserting another cylindrical member inside the cylindrical member before welding is press-fitting, the deformation of the cylindrical member deformed by the press-fitting can be corrected by welding.
[0014]
According to the welding method of the second aspect of the present invention, since the cylindrical members are welded to each other using the welding apparatus according to the first aspect, deformation due to welding is prevented and the welded portion that has been deformed before welding is prevented. The shape can be corrected.
Also, the cylindrical member is welded by energy applied from one of the application means adjacent in the circumferential direction while the cylindrical member is welded relative to the application means while rotating the cylindrical member relative to the application means. Then, it is melted again by the energy applied from the other of the application means adjacent in the circumferential direction. Even if pores are generated in the welded portion of the cylindrical member that has been melted and welded by the energy applied from one adjacent application means, the welded portion in which the pores are generated by the energy applied from the other adjacent application means is melted again. The pores disappear by the second melting.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, examples showing embodiments of the present invention will be described with reference to the drawings.
A welding apparatus according to an embodiment of the present invention is shown in FIG.
The outer cylinder member 10 and the inner cylinder member 11 are cylindrical members having the same cross section, and the inner cylinder member 11 is press-fitted inside the outer cylinder member 10. As the outer cylinder member 10 and the inner cylinder member 11, for example, a combination of an injector housing and a nozzle body is conceivable.
[0016]
The laser generator 1 as an energy source generates a high energy laser such as YAG or CO ₂ . The spectroscope 2 splits the laser generated by the laser generator 1 in two directions. The split laser is emitted toward the outer cylinder member 10 from the two optical heads 20 as application means. The optical head 20 is separated from the outer cylinder member 10 and the inner cylinder member 11 by approximately 90 ° in the circumferential direction on the plane orthogonal to the center axis of both cylinder members and centering on the center axis in the longitudinal direction of both cylinder members. Are arranged. The laser 30 irradiated from the optical head 20 toward the outer cylindrical member 10 is irradiated along a plane orthogonal to the central axis of both cylindrical members. The outer cylinder member 10 and the inner cylinder member 11 are melt-welded over the entire circumference by the laser 30 irradiated from the optical head 20. An arc discharge or an electron beam may be used as high energy for melting and welding both the cylindrical members.
[0017]
When the outer cylinder member 10 and the inner cylinder member 11 are melt welded over the entire circumference, the outer cylinder member 10 and the inner cylinder member 11 which are members to be welded are rotated with respect to the optical head 20. If possible, the optical head 20 may be rotated about both cylinder members. The outer cylinder member 10 and the inner cylinder member 11 are rotated at least once or more so that the laser 30 at the rear in the rotation direction is melted again at the portion where the laser 30 at the front in the rotation direction is melted.
[0018]
Next, the fusion welding by the welding apparatus of a present Example is demonstrated. 3 and 4 indicate the inner and outer diameters of the deformed welded part.
The optical heads 20 are disposed outside the outer cylinder member 10 at approximately 90 ° intervals, and two portions of the outer cylinder member 10 and the inner cylinder member 11 that are approximately 90 ° apart in the circumferential direction are melted and welded. When melt welding is performed by applying the laser 30 only from one direction, both cylinders are caused by the relative thermal strain balance between the unmelted portion, the portion irradiated with the laser 30 and melted, and the portion that has started to solidify. The member tends to deform in a direction perpendicular to the irradiation direction of the laser 30.
[0019]
In the present embodiment, the laser beam is applied to a portion of the outer cylinder member 10 that is approximately 90 ° apart, so that the outer cylinder member 10 and the inner cylinder member 11 are deformed by the laser 30 irradiated from one optical head 20. The laser 30 is irradiated by the other optical head 20. Accordingly, as shown in FIG. 2, the directions in which the outer cylinder member 10 and the inner cylinder member 11 are to be deformed are orthogonal to each other, and are deformed uniformly as a whole.
[0020]
As shown in FIG. 3A, if the processing accuracy of both cylinder members is high and the shape 50 before welding is close to a perfect circle, the shape 51 after welding shown in FIG. 3B is also a perfect circle. Keep close shape. Moreover, as shown to (A) of FIG. 4, even if the process precision of both cylinder members is low and the shape 60 before welding deform | transforms, since both cylinder members deform | transform equally in the orthogonal direction, ( The welded shape 61 shown in B) is corrected for deformation and becomes a shape close to a perfect circle.
[0021]
If foreign matter or the like is mixed in the welded portion of the outer cylindrical member 10 and the inner cylindrical member 11, the welded portion containing the foreign matter is melted by the laser 30 irradiated from one optical head 20, so that FIG. As shown in FIG. 2, the portion where the foreign matter in the welded portion 70 is mixed remains as a pore 71. When this welding spot 70 is irradiated with the laser 30 from the other optical head 20 and the welding spot 70 is melted again, the pores 71 disappear.
[0022]
The welding apparatus of the present embodiment is used, for example, to weld the cylindrical members of the injector 100 shown in FIG. Among the members constituting the injector 100, the valve housing 101, the valve body 110, the valve member 120, the movable core 122, and the magnetic member 135 correspond to the cylindrical members described in the claims. In FIG. 6, black triangles 150 are portions where the cylindrical members are welded all around. First, the configuration of the injector 100 will be described.
[0023]
A valve housing 101 which is a housing member of the injector 100 is integrally formed in order of the first magnetic portion 102, the nonmagnetic portion 103 as the magnetic resistance portion, and the second magnetic portion 104 from the lower fuel injection side in FIG. . The first magnetic part 102 and the second magnetic part 104 are magnetized, and the nonmagnetic part 103 is made nonmagnetic by heating a part of the valve housing 101. The fuel injection side inner peripheral wall of the first magnetic part 102 is coupled to the outer peripheral wall of the valve body 110 by welding. The valve housing 101 accommodates the valve member 120 and the movable core 122 so as to be capable of reciprocating.
The cup-shaped nozzle hole plate 112 is joined to the outer peripheral wall of the valve body 110 by welding, and is sandwiched between the valve body 110 and the support member 114. The nozzle hole plate 112 is formed in a thin plate shape, and a plurality of nozzle holes 112a are formed at the center.
[0024]
The valve member 120 is formed in a bottomed cylindrical shape, and a contact portion 121 is formed on the bottom side of the valve member 120. The contact portion 121 can be seated on a valve seat 111 formed on the inner peripheral wall of the valve body 110. A cylindrical movable core 122 is fixed to the valve member 120 on the side opposite to the injection hole of the valve member 120 by welding. A plurality of fuel holes 120 a penetrating the side wall of the valve member 120 are formed on the upstream side of the contact portion 121. The fuel that has flowed into the valve member 120 passes from the inside to the outside through the fuel hole 120a and travels toward the seat portion formed by the contact portion 121 and the valve seat 111.
[0025]
When the contact portion 121 is seated on the valve seat 111 by the biasing force of the spring 125, the injection hole 112a is closed and the fuel injection is shut off. When the movable core 122 is attracted to the fixed core 130 by energizing the coil 140 as electromagnetic driving means and the valve member 120 is separated from the valve seat 111 together with the movable core 122, the injection hole 112a is opened and fuel injection is allowed. .
[0026]
The fixed core 130 is installed on the side opposite to the injection hole of the movable core 122 and faces the movable core 122. One end of the spring 125 is locked to the adjusting pipe 131, and the other end is locked to the movable core 122. The spring 125 urges the valve member 120 toward the valve seat 111.
[0027]
The magnetic members 135 and 136 are installed on the outer peripheral side of the coil 140 as electromagnetic driving means. The magnetic members 135 and 136 magnetically connect the first magnetic part 102 and the fixed core 130 via the second magnetic part 104. The fixed core 130, the movable core 122, the first magnetic unit 102, the second magnetic unit 104, and the magnetic members 135 and 136 constitute a magnetic circuit.
[0028]
The first magnetic part 102 and the valve body 110 are welded by the above-described welding method using the welding apparatus shown in FIG. 1 with the valve body 110 inserted inside the first magnetic part 102. The magnetic member 135 and the first magnetic part 102 are welded by the above-described welding method using the welding apparatus shown in FIG. 1 with the first magnetic part 102 inserted inside the magnetic member 135. The movable core 122 and the valve member 120 are welded by the welding method described above by inserting the valve member 120 inside the movable core 122 and using the welding apparatus shown in FIG.
[0029]
Since the roundness of the welded portion of each cylindrical member constituting the injector 100 is improved, misalignment between the valve body 110 and the valve member 120 is reduced, and the valve member 120 is seated on the valve seat 111. Sometimes the gap formed between the valve seat 111 and the valve member 120 is reduced. Since the seat property of the valve seat 111 and the valve member 120 is improved, the oil tightness is improved as shown in FIG. In FIG. 7, oil tightness represents the amount of fuel leaking from between the valve seat 111 and the valve member 120 when the valve member 120 is seated on the valve seat 111.
[0030]
In the above-described embodiment of the present invention described above, the two optical heads 20 are arranged on the outer periphery of the outer cylindrical member 10 as 90 degrees apart as application means. The angle formed between the optical heads 20 is not limited to 90 °, and the angle formed between the optical heads 20 around both cylindrical members may be 80 ≦ θ ≦ 100. Moreover, although the laser 30 was irradiated along the plane orthogonal to the central axis of both cylinder members, you may irradiate diagonally with respect to the central axis.
[0031]
The number of optical heads 20 is not limited to two, but three or more optical heads 20 are arranged outside the outer cylindrical member 10 at substantially equal angular intervals, and the outer cylindrical member 10 and the inner cylindrical member 11 are melt welded. May be. When three or more applying means are arranged, assuming that the number of applying means is n and the angle formed by the optical heads 20 adjacent to each other in the circumferential direction around the cylindrical members is θ °, (360 / n) − The optical head 20 is disposed so as to satisfy 10 ≦ θ ≦ (360 / n) +10. However, the number of optical heads 20 that can be arranged is limited to about 10 due to the configuration of the welding apparatus.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing a welding apparatus according to an embodiment of the present invention.
FIG. 2 is an explanatory view for explaining deformation due to welding of both cylindrical members according to the present embodiment.
FIGS. 3A and 3B are schematic explanatory views showing changes in cross-sectional shape of both cylindrical members with high processing accuracy according to the present embodiment, where FIG. 3A shows a cross-sectional shape before welding and FIG. 3B shows a cross-sectional shape after welding.
4A and 4B are schematic explanatory views showing changes in cross-sectional shape of both cylindrical members with low processing accuracy according to the present embodiment, where FIG. 4A shows a cross-sectional shape before welding, and FIG. 4B shows a cross-sectional shape after welding.
FIG. 5 is a schematic cross-sectional view showing a change in a welded part by two-time welding.
FIG. 6 is a cross-sectional view showing an injector for welding using the welding apparatus of the present embodiment.
FIG. 7 is a characteristic diagram showing the relationship between roundness and oil tightness of a cylindrical member constituting the injector.
FIG. 8 is a schematic perspective view showing a welding apparatus according to Conventional Example 1;
FIGS. 9A and 9B are schematic explanatory views showing changes in the cross-sectional shape of both cylindrical members according to Conventional Example 1, FIG. 9A shows a cross-sectional shape before welding, and FIG. 9B shows a cross-sectional shape after welding.
10 is a schematic perspective view showing a welding apparatus according to Conventional Example 2. FIG.
11A and 11B are schematic explanatory views showing changes in cross-sectional shapes of both cylindrical members according to Conventional Example 2, wherein FIG. 11A shows a cross-sectional shape before welding and FIG. 11B shows a cross-sectional shape after welding.
[Explanation of symbols]
1 Laser generator (energy source)
2 Spectrometer 10 Outer cylinder member (cylindrical member)
11 Inner cylinder member (cylindrical member)
20 Optical head (applying means)
30 Laser 100 Injector 101 Valve housing (housing member, cylindrical member)
110 Valve body (cylindrical member)
120 Valve member (cylindrical member)
122 Movable core (cylindrical member)
135, 136 Magnetic member (cylindrical member)
140 coil (electromagnetic drive means)

Claims (2)

It is a welding apparatus that inserts another cylindrical member inside the cylindrical member and melts and welds the cylindrical members in the circumferential direction,
An energy source that generates energy for melting and welding the cylindrical members, and an application unit that applies energy generated by the energy source to the cylindrical member;
The application means is arranged at two places in a circumferential direction on a plane orthogonal to the central axis of the cylindrical member, and the application means for melting and welding two places separated in the circumferential direction of the cylindrical member attach the cylindrical member to each other. A welding apparatus, wherein an angle formed as a center is θ °, and 80 ≦ θ ≦ 100. A welding method for welding using the welding apparatus according to claim 1,
With the central axis of the cylindrical member as the rotation axis, the cylindrical members are welded together while rotating the cylindrical member relative to the application means, and the location of the cylindrical member melted by energy applied from one of the application means is A welding method characterized by melting again by energy applied from the other of the application means.

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